Several bootloaders exist. Each one of them has its own way of
configuration. In this chapter we'll describe all possibilities for you
and step you through the process of configuring a bootloader to your
needs.
10.02010-07-20Making your ChoiceIntroduction

Now that your kernel is configured and compiled and the necessary system
configuration files are filled in correctly, it is time to install a
program that will fire up your kernel when you start the system. Such a
program is called a bootloader.

On Linux/PPC64 we have only yaBoot as a bootloader until grub2 is
finished.

Using yaBootIntroduction
If you are using a 64-bit userland, you must use the yaboot-static
package because yaboot cannot be compiled as a 64-bit application. The 32-bit
userlands should use the regular yaboot package.

There are two ways to configure yaBoot for your system. You can use the new and
improved yabootconfig included with yaboot-1.3.8-r1 and
later to automatically set up yaboot. If for some reason you do not want to run
yabootconfig to automatically set up /etc/yaboot.conf or you
are installing Gentoo on a G5 (on which yabootconfig does not always
work), you can just edit the sample file already installed on your system.

yabootconfig/ybin won't work on IBM. You have to install yaboot another way:
Using yaboot on IBM hardware
If your root filesystem uses the JFS filesystem, be sure to add ro as a
kernel parameter. JFS must be able to replay its log in read-only mode before it
gets mounted read-write.

Default: Using yabootconfig

Alternative: Manual yaBoot Configuration

Default: Using yabootconfig

yabootconfig will auto-detect the partitions on your machine and will
set up dual and triple boot combinations with Linux, Mac OS, and Mac OS
X.

To use yabootconfig, your drive must have a bootstrap partition, and
/etc/fstab must be configured with your Linux partitions. Both of
these should have been done already in the steps above. To start, ensure that
you have the latest version of yaboot installed by running emerge --update
yaboot-static. This is necessary as the latest version will be available via
Portage, but it may not have made it into the stage files.

Now run yabootconfig. The program will run and it will confirm the
location of the bootstrap partition. Type Y if it is correct. If not,
double check /etc/fstab. yabootconfig will then scan your system
setup, create /etc/yaboot.conf and run mkofboot for you.
mkofboot is used to format the bootstrap partition, and install the
yaboot configuration file into it.

You might want to verify the contents of /etc/yaboot.conf. If you
make changes to /etc/yaboot.conf (like setting the default/boot
OS), make sure to rerun ybin -v to apply changes to the bootstrap
partition.

Now continue with Rebooting your System.

Alternative: Manual yaBoot Configuration

First make sure you have the latest yaboot-static installed on your
system:

## /etc/yaboot.conf
##
## run: "man yaboot.conf" for details. Do not make changes until you have!!
## see also: /usr/share/doc/yaboot/examples for example configurations.
##
## For a dual-boot menu, add one or more of:
## bsd=/dev/sdaX, macos=/dev/sdaY, macosx=/dev/sdaZ
## our bootstrap partition:
boot=/dev/sda2
## ofboot is the Open Firmware way to specify the bootstrap partition.
## If this isn't defined, yaboot fails on the G5 and some G4s (unless
## you pass the necessary arguments to the mkofboot/ybin program).
## hd:X means /dev/sdaX.
ofboot=hd:2
## hd: is Open Firmware speak for sda
device=hd:
delay=5
defaultos=macosx
timeout=30
install=/usr/lib/yaboot/yaboot
magicboot=/usr/lib/yaboot/ofboot
#################
## This section can be duplicated if you have more than one kernel or set of
## boot options - replace with your kernel
#################
image=/boot/
label=Linux
root=/dev/sda3
partition=3
read-only
macos=hd:13
macosx=hd:12
enablecdboot
enableofboot

Once yaboot.conf is set up the way you want it, you run mkofboot
-v to install the settings in the bootstrap partition. Don't forget
this! Confirm when mkofboot asks you to create a new filesystem.

If all goes well, and you have the same options as the sample above, your next
reboot will give you a simple, five-entry boot menu. If you update your yaboot
config later on, you'll just need to run ybin -v to update the bootstrap
partition - mkofboot is for initial setup only.

For more information on yaboot, take a look at the yaboot project. For now,
continue the installation with Rebooting your System.

Using yaboot on IBM hardware

On IBM hardware you cannot run yabootconfig or ybin. You must
proceed with the following steps:

Install yaboot-static

Run dd if=/usr/lib/yaboot/yaboot.chrp of=/dev/sdXX (fill in XX with
your disk and partition for the PReP partition; this was in our example
/dev/sda1)

Next construct your own yaboot.conf file and place into
/etc. (Take a look at the config above, look into the man page
of yaboot.conf or look at the below yaboot.conf example.)

Assuming your boot device in OF is pointing to the harddrive you prep boot
partition is on then it'll just work, otherwise at IPL time, go into the
multiboot menu and set the boot device to the one with your prep boot
partition

For POWER4, POWER5, and blade-based hardware where the PReP disk partition and
the disk partition that contains your kernel are on the same physical disk, you
can use a simplified yaboot.conf. The following should be
sufficient: